1. Field of the Invention
The present invention relates to a protective cover for a connector, and more particularly to a protective cover for a connector for protecting a terminal engaging portion of a connector in which a lock arm for retaining a connector engaging portion on a mating side is provided projectingly on an outer peripheral wall of a housing.
2. Description of the Related Art
Conventionally, in a connector used in a wire harness or the like for a vehicle, there is a possibility of dust entering through an opening of a terminal engaging portion formed at a front end of a terminal accommodating chamber during such as storage or transport prior to being engaged with a connector engaging portion on a mating side, possibly resulting in faulty contact. In addition, in the case of a connector in which a lock arm for retaining the connector engaging portion on the mating side is provided projectingly on an outer peripheral wall of a housing, since the lock arm is exposed to the outside, there is a possibility that the lock arm undergoes plastic deformation or a lock projection becomes damaged due to an external force or contact with other equipment.
Accordingly, as shown in FIG. 5, a protective cover 1 for a connector is fitted over a terminal engaging portion 2a of a connector 2 so as to prevent dust and protect a lock arm 7.
The connector 2 has a structure in which the lock arm 7, which is formed in such a manner as to project from an outer peripheral wall of a housing 5 for accommodating a plurality of wire-attached terminals 4 in an arranged form, has the following: a flexible arm 7a extending rearwardly from a terminal-engaging-portion front end side of the outer peripheral wall via a front upright proximal portion; an engaging projection 7b formed on the flexible arm 7a and serving as an engaging portion; and a tab portion 7c formed on a free end side of the flexible arm 7a. The engaging projection 7b can be engaged with or disengaged from a retaining means provided in a connector engaging portion or the like on the mating side, through a tilting operation in which the tab portion 7c is depressed toward the outer peripheral wall of the housing as indicated by arrow (C) in FIG. 5. Incidentally, in this case, the retaining means provided on the mating connector or the connector engaging portion of an electric or electronic equipment or the like is a recessed portion or a stepped portion capable of retaining the engaging projection 7b.
The protective cover 1 is comprised of a substantially box-shaped cover body 8 which is fitted over the front end side of the housing 5 and covers a tip opening of the terminal engaging portion 2a of the connector 2, as well as a coupling retaining means 9 which is provided on the cover body 8 in such a manner as to be capable of engaging the engaging projection 7b when the cover body 8 is fitted over the housing 5, and of being disengaged from the engaging projection 7b by the tilting operation of the flexible arm 7a. The coupling retaining means 9 has the same structure as the retaining means provided on the mating connector or the connector engaging portion of an electric or electronic equipment or the like, i.e., a connecting counterpart of the connector 2, and is formed as an engaging groove into which the engaging projection 7b plunges when the amount of the housing 5 fitted into the cover body 8 reaches a predetermined amount.
Then, when the protective cover 1 is properly fitted over the front end side of the housing 5, the engaging projection 7b on the lock arm 7 of the connector 2 is engaged with the coupling retaining means 9 of the protective cover 1. As a result, the protective cover 1 is set in a state of being held and fixed by the connector 2, and the tip opening of the terminal engaging portion 2a of the connector 2 is set in a state of being covered with the protective cover 1.
However, in the above-described protective cover 1, the tab portion 7c of the lock arm 7 projects outwardly of the protective cover 1, so that there has been a possibility that if another member or the like strikes against the tab portion 7c during storage or the like, the lock arm 7 becomes depressed, which cancels the engagement between the engaging projection 7b and the coupling retaining means 9, causing the protective cover 1 to slip off.
In particular, in a case where the connector 2 is a connector for a flexible printed circuit board (FPC) where spring portions of wire-attached terminal are exposed at its terminal engaging portion, such as a connector for a meter of a vehicle, to prevent the deformation of the spring portions the laying operation of the wire harness must be effected with the protective cover 1 fitted thereto until immediately before the engagement with the mating connector engaging portion.
Accordingly, as shown in FIG. 6, in a case where the connector 2 is inserted in a connector insertion hole 11a formed in an instrument panel 11, the connector 2 is inserted with the protective cover 1 fitted thereon. However, there is a problem in that, at that juncture, unless the size of the opening of the connector insertion hole 11a is sufficiently large, an edge of the connector insertion hole 11a can strike on the tab portion 7c during the inserting operating, which depresses the lock arm 7, thereby causing the protective cover 1 to fall inside the instrument panel 11.
Accordingly, to prevent the occurrence of such a problem, a protective cover 12 for a connector such as the one shown in FIGS. 7 and 8 has been proposed.
The protective cover 12 is disclosed in Japanese Patent Unexamined Publication No. Hei. 8-273745, and a pair of flexible lock walls 14 for the lock arm 7 are provided projectingly on an inner surface of substantially box-shaped cover body 13 which is fitted over the terminal engaging portion 2a of the connector 2. Retaining projections 14a which engage a front upright proximal portion of the lock arm 7 rising from the housing 5 are respectively provided on the pair of flexible lock walls 14.
Namely, when the terminal engaging portion 2a of the connector 2 is inserted into the protective cover 12, the retaining projections 14a on the pair of flexible lock walls 14 engage the back of the front upright proximal portion, and are locked with respect to the connector 2, as shown in FIG. 8. Accordingly, even if the tab portion 7c is depressed, the engagement between the engaging projection 14a and the lock arm 7 is prevented from becoming canceled and the protective cover 12 is prevented from coming off the connector 2, thereby preventing unintentional coming off of the protective cover 12.
However, with the protective cover 12 shown in FIGS. 7 and 8, the state of engagement between the lock arm 7 and the pair of retaining projections 14a cannot be canceled by the tilting operation in which the tab portion 7c of the lock arm 7 is depressed. To remove the protective cover 12 from the connector 2, the cover body 13 must be forcibly pulled to thereby resiliently deform the pair of flexible lock walls 14 on the inner sides of the cover body 13.
Accordingly, if the engaging strength of the retaining projections 14a is set high so as to prevent the cover body 13 from coming off the connector 2 unintentionally, a force is required for removing the cover body 13, and removal becomes difficult. Hence, there arises the problem that the operating efficiency in the attachment of the protective cover 12 to the connector and the removal thereof from the connector declines as compared with the protective cover 1 shown in FIG. 6. In addition, in the protective cover 12, since the tab portion 7c of the lock arm 7 is not protected, the tab portion 7c is liable to be caught at the opening edge of the connector insertion hole 11a when the connector 2 is inserted into the connector insertion hole 11a, so that the operating efficiency in insertion is not satisfactory.
Further, in the case where the cover body 13 itself is provided with finger applying portions 15 which are caught by fingers, as shown in FIG. 7, there is a problem in that the protective cover 12 becomes large in size and bulky. Moreover, since the pair of flexible lock walls 14 which are adapted to undergo resilient deformation must be provided on the inner sides of the cover body 13, there is a problem in that the structure of a mold for the protective cover 12 becomes complex, resulting in higher cost.